There are various possible abnormal conditions or irregularities taking place in a sewing machine, such as thread breakage, stitch skipping or stitch leaving out, needle breakage, etc. Causes thinkable for each of those abnormal conditions are generally plural, so an operator is usually obliged to check all of imaginable causes for each abnormal condition, so as to solve the problem of such abnormal conditions. This checking operation of the existence of those causes of abnormal conditions has been an extremely tiresome and time consuming work, because of multifunction of the sewing machine and a variety of such causes in recent days. This kind of checking performed with reference to an instruction manual booklet creates a great burden for the operator, particularly so for a household operator who is not so familiar with machinery.